[RFI] TVI filters

[Paul Christensen]

> Another important point I forgot to mention. Virtually all problems
> with RF actually getting into the cable system (and showing up on
> the center conductor of the coax) are caused by poorly crimped F-
> connectors, or other forms of poor termination, like a non-technical
> user trying to extend his cable wiring.

As a former Director of Engineering for Comcast, the most prevalent form of 
ingress occurs through loose F-connectors, most of which are properly 
crimped.  That, followed by improperly-crimped connectors as Jim point out. 
Even the slightest amout of a loosening of an F-connector will allow 
ingress.  Nearly every cable technician keeps a 7/16" open wrench in his or 
her back-pocket.  It gets grabbed in the morning as s/he dresses.<g>

Back in the mid-'90s, we conducted an extensive study on ingress and found 
significant differences among cable and connector quality.  Not too 
surprising, the most effective combination is quad-shielded cable with 
compression connectors (e.g., Thomas & Betts/LRC "Snap-'N-Seal").   Any CATV 
cabling used outdoors performed significantly better over time if it was of 
the gel-flooded variety.

Paul, W9AC